Fuse lead construction for electric lamps



Dec. 19, 1939. w, E, ANDERSON 2,183,952

FUSE LEAD CONSTRUCTION FOR ELECTRIC LAMPS Filed' May 15, 1938 2sheets-sheet 1 d lNvENToR 45 fz K 7 WM5/amm v SYS i f V ATTO R N EY Dec.19,l 1939. w. E. ANDERSON FUSE LEAD CONSTRUCTION FOR ELECTRIC LAMPS-Filed May l5, 1938 2 Sheets-Sheet 2 BYE1 n ATTORNY Patented Dec. '19,19439 UNITED STATESv lPrxrlzN'r OFFICE 2,183,952 Y FUsE LEADCONSTRUCTION Foa ELECTRIC LAMPS of Pennsylvania ApplicationvkMay 13,1938, Serial No. 207,704

lI8 Claims.

This invention relates to electric 'lamps and more particularly to theconstruction of the fuse lead in high wattage lamps generally designatedas bipost lamps. Y

During recent years it has become the practice to use fuses in certainclasses of gas-filled lamps, for protection against destructive arcsupon failure of the lamp filament. The designs'commonly used previouslyeither incorporate the fuse elebulb; fo'r example, in the stem-tubebetween the press and thebase, or internal as a part of the inner leadbetween the press and the filament. In both designs, however, the fusehas always been of the series type kwhere the lead is assembled bybutt-welding the different parts together one after the other.

In bipost lamps, however, only the internal type of fuse is practicablyapplicable and since the lead wires must carry the entire mechanicalload of the internal structure of the lamp, as well as the current, theseries type of fuse introduces a weak link in the supporting structurewhich necessitates the use of expensive bracing parts to permit shippingthe lampV and to withstand ordinary handling by the user. Likewise, thesecondary arc produced by the operation of the fuse, when the lamp failshot, tends to maintain itself between the ends of the adjacent largerparts of the lead wires, producing a comparatively large amount of hotmetal and fuse cover material which scatters onto the bulb, resulting inconsequent danger of breakage or explosion.

To overcome such objections, as well as avoid the necessity forAexpensive butt-welding equipment, I have designed and demonstrated inlamps, a fuse lead construction which not only eliminates hazards fromsecondary arcs produced by the operation of the fuse itself, andprovides a rigid structure to withstand shipping and handling; but isalso much less expensive to manufacture.

It is, therefore, a principal object of my invention to provideagas-filled lamp, particularly of the bipost construction, comprising arigid mount including a fuse, in order to avoid destructive arcs uponfailure of the lamp, said mount p weld fuses and substitutes what mightbe termed a shunt fuse arrangement.

A still further object of my invention is the formation of aconstruction for lamps in which a fuse is so enclosed that arcing, uponfailure of the lampandthe operation of the fuse, is minimized.

Other objects and advantages of the invention relating to the particulararrangement and con- .struction of the various parts will becomeapparent as the description proceeds.

. In the drawings:

Fig. 1 is a side elevational view of anl incandescent electric lamp ofthe bipost type embodyingv my invention.

Fig. 2 is an enlarged detail view of the fuse portion of the lamp ofFig. l, partly on line II-II .of Fig. 3, in the direction of the arrows.

Fig. 3 is an enlarged horizontal sectional View ,on the line III-III ofFig. 2, in the direction of the arrows.

Fig. 4 is an elevational view of the base and vleads of the lamp of Fig.1, prior to insertion o the fuse.`

Fig. 5 is a partial elevational and partial vertical sectional view, asin Fig. 2, of a fuse for a lamp such as shown in Fig. 1, butillustrating a modification.

Fig. 6 is a view corresponding to Fig. 5, but showing another embodimentof my invention.

Fig. 'l is a fragmentary view of a portion of a bipost lampcorresponding generally to Fig. 1, but showing another embodiment of myinvention. Y

Fig. 8 is an enlarged detailed view of the fuse lead, on the lineVIII-VIIIv of Fig. 7, in the direction ofthe arrows.

Fig. 9 is an enlarged horizontal sectional View of said lead on the lineIX-IX of Fig. 7, in the direction of the arrows.

Fig. 10 is an elevational view of a mount for another embodiment of myinvention.

Fig. 11 is ay fragmentary elevational view on the line XI-EH of Fig. 10,in thedirection of the arrows.

Fig. 12 is an enlarged horizontal sectional view on the line XII-XII ofFig. 10, in the direction of the arrows.

' Referring to the drawings Ain detail, like parts4 being designated bylike reference characters, and first considering the embodiment of myinvention illustrated in Figs. 1 to 4, inclusive, there is shown ahigh-wattage lamp I4, of the medium bipost type, comprising an envelopeI5 provided with a base I6, through which extend leading-in conductorsI1 and |8 from terminal posts I9 and 2|.

The leading-in conductors I1 and I8 may be formed hollow to receive theconductors orsupport leads 22 and 23, the lower ends of which may besecured to said conductors I1 and I8 in 4any desired manner as'bycrimping, asindicated at 24 and 25. The free or upper ends of theconductors 22 and 23 are, in the present embodlrnent, connected by wires25 and 21, the outer ends of which are spot-Welded thereto, and theinner ends embedded in a glass or other insulating portion 28.Intermediate portions of the conductors 22 and 23 are likewise connectedby wires 29 and `3|), the outer ends of which are embedded in a glass orother insulating portion 3|.

The filament 32, illustrated as of the coiled variety, is shown mountedbetween the conduc- ,tors 22 and 23 and the insulators 28 and 3|, the

end' sections 20 of said filament being fitted over stifiening wires 40,and filament and wires welded or otherwise secured to the conductors 22and 23, and the intermediate portions draped over hooks 33, 34, and 35,extending from the insulator 28 and hooks 38 and 31, extendingfrom thecorresponding insulator 3|.

The insulators 28 and 3| also desirably carry wires or spuds which serveto support screens .or other means for Icollecting material vaporizedfrom the filament, thereby minimizing the blackening of the bulb. 4Forthis purpose, the insulator 28 has spuds or support wires 38 and 39which extend'laterally therefrom and to which.

from opposite sides of the insulator 28.'.

In the same way, a vaporized metal collecting screen 42 is desirablysupported from the insulator 3| by spuds or wires 43 and 44 extendingfrom the sides thereof and to which the screen is desirably spot-welded.The screen 42 is desirably V-shaped, like the corresponding screenillustrated in Fig. 11 and straddles the insulator 3|, .like the screen4| thereabove. l When the envelope I5 has been filled with an inert gasand sealed, the lamp, as just described, is one of the high-wattagetype, suitable for projectioni'or general lighting purposes. On accountof carrying the necessaryvhigh current, failure of the filament is aptto result in a destructive arc between the adjacent ends of saidfilament. In order to avoid such an arcing,^I provide, in the presentembodiment, a fuse 45 for the conductor 23. 'I'his fuse may be insertedby cutting the conductor 23 at the point 48, as shown in Fig. 4, as bymeans of shears 41, and then fitting an insulating lead-bracing tube 48over vthe stub 49 of the conductor 23, as shown most clearly in Fig. 2.

After applying a glass or refractory bead 5| 'in the tube 48 above thefree end of the stub 49, I thereafter insert the portion 52 of theconductor 23, which was cut off in the operation described in connectionwith Fig. 4, thereby rigidly uniting the adjacent ends of the portions49 fractory like lava, being mentioned as an example, but, if desired, aglass tube may instead be satisfactorily used.

The fuse 45 of the present embodiment is formed as'a wire of nickel, orother suitable fuse material, of sufficientI cross section to carry thenormal current without overheating, but which will fail by fusion uponthe passage of excessive current which might flow upon the formation ofan arc between the broken ends of the filament 32. The fuse 45 has mostof its length enclosed in a tube 53, which may be of materialcorresponding with that of the tube 48, that is of Alsimag, glass, orthe like, as desired. The free i ends of thewire 45 are desirably woundaround the lead sections 49 and 52 and spot-welded thereto, as indicatedat 54 and 55, thereby tightly holding said lead portions together andpreventing their removal from the tube 48.

By positioning the fuse 45 parallel to the adjacent ends of thesupporting lead sections 49' and 52,1 provide a structure which issufiiciently rigid to withstand shipping and handling and is also muchless expensive to manufacture. The close fitting refractory or'glasstube 48 provides rigidity for the lead 23, practically equivalent tothat before cutting, and the fuse 45, of suitable size and material,ties the two parts of the main lead together, producing a rigid unit.With a close fitting refractory, tube 53, over the fuse, the actionthereof is of the expulsion type;,that is, melting occurs inside, ratherthan outside, of the tube 53, due to said tube acting as a heatinsulator, whereby upon melting, the metal vapors formed forcibly blowout the fuse sections at the ends of the cover tube, thereby quenchingthe arc formed by blowing it apart. Lamps manufactured with this type offuse lead construction have shown it to be effective.

Referring now to the embodiment of my invention illustrated in Fig. 5,the fuse lead 23a is there shown interrupted and provided with a portion45 reduced in section to correspond with that of the fuse 45 of thepreceding embodiment. This section is desirably constructed of a piece 1of nickel, or other suitable fuse material, of proper dimensions toprovide the desired fuse characteristics, and has its ends secured tothe adjacent ends of the heavy lead portions 49a and 52, as by welding,indicated at 54"v and 55.

The composite lead 23' then has applied thereover a refractory, glass,or other insulating tube 48, desirably closely fitting the heavy leadportions 49,and 52, and secured in place in any desired manner asbymeans of metal spuds 56 and 51, welded or otherwise secured to thelead sections 49I and 52 adjacent the ends of the tube 481. Inlthepresent embodiment, the leadbracing tube 48n is shown provided with ahole 58 in its side, pointing away from the other lead (not shown), sothat the air will be efficiently exhausted therefrom during manufactureof the lamp, and any vapors formed during melting of the fuse 45t aredischarged away from said other lead.

Fig. `6 illustrates an embodiment of my invention correspondingk with'the fuse arrangement of Fig. 5, with modified features. Although thetube 48" preferably closely fits the lead sections 49b and 52", it need\not fit closely, as the construction is here rigidifled by coils ofwirev 59 and 60 which closely surround the ends of the lead-bracing tube48b and have their outermost ends coiled around the lead sections 491and 52b and welded or otherwise secured thereto, as indicated at 8l and82. If the tube 48b loosely nts the sections 49b and 52, the aperture 88may be omitted as the space around loose-fitting sections serves thesame purpose. It will therefore be seen that this construction providesadditional rigidity by securing the ends of the tube 48b to the mainlead sections 49b and 52b by supplemental wire portions, in addition tothe fitting of the lead sections in the tube itself.

Referring Inow to the embodiment of my invention illustrated in Figs. 7,8, and 9, there is shown a fragmentary portion of a medium bipost lampI4 comprising an envelopel5 provided with a base |8 through which extendleading-4 in conductors I1 and I8, from terminal posts I9 and 2I.

Extending from the conductors I1 and I8 are I support leads 22 and v23connected by wires 29 and 30, the outer ends of which are spot-welded'thereto and the inner ends embedded in a glass or other insulatingportion 31. Although only the lower bracing device 29, 89, 8I is shown,it will be understood that the upper ends of the support leads aredesirably connected by a bracing device similar to that shown in Fig. land designated by the reference characters 26,21, 28. However, thefilament may instead be supported as in the embodiment of Figs; 10, 11,and 12. Between the leads. 22, 23, and the bracing devices, or above orbeyond the bracing device, is 'mounted an' incandescible filamentdesirably Y corresponding with that designated by the referencecharacter32 in Fig. 1. As in Fig. l, screens, or only one, as shown anddesignated by the reference character 42, may be employed for collectingvaporized filamentary material during operation of the lamp.

In the present embodiment, the-lead 23 is formed in two sections: alower section 49 and an upper section 52. The section 49 is secured to ametal connector plate 63 as by welding, and the section 52 is secured toa similar metal connecting plate 64, desirably in the same manner. Theseplates are 'separated by an insulating plate of mica or other suitablematerial 65, and held in` assembled relation, as illustrated, by bolts66 and nuts 61 passing through associated insulating washers 68 and 89,and suitable aper'- tures in the associated plates 83, 84, and 85, inorder` to rigidly connect the parts 49 and 52, forming the support lead23, while insuring that said parts are insulated from one another.

As ingtheembodment of Figs. 1 to 4,k inclusive, I provide a bipass orparallel fuse device 1l r which, in the present embodiment, consists ofterminal wires'12 and 13 tightly fittingin the ends of an insulatingbracing tube 48 formed 0f refractory material or glass, like the tube 48of the first embodiment. Between the enclosed end portions of theterminal wires 12 and 13 which form in effect extensions of the leadsections 52 and 49, extends a fuse wire 45, which may correspond withthe fuse wire 45 ofthe first embodiment. The ends of the members 12 and13 are desirably bent at right angles to the tube 48 and respectivelysecured to the upper .lead section 52 and the lowerlead section 49, asby spot-welding or inany desired manner, thereby further rigidifying theconnection between the lead sections 49 and 52.

Referring now to the embodiment of my invention illustrated in Figs. 10,11, and l2, there is disclosed a mount for a medium bipost lamp, saidmount being provided with a base I8 and leading-in conductors I1.and l8having terminal posts |9 and 20. Extending from the conductor I1, is arelatively thick or heavy 'support lead 22, to the upper end of which issecured an angular extension 14, as by spot-welding indicated at 15, anda short piece of wire or spud 18 carrying a glass insulator 11.

Extending from the leading-in conductor I8 is a relatively thin or lightsupport lead 23 formed as a lower section 49, and an upper section 52,said sections having their adjacent ends tightly fitted in an insulatingbracing tube 48. formed of glass or refractory material, andelectrically connected by a .fuse wire 45 extending through said tube.In order to further brace the relatively light fused lead 23, the tube48 is bound vto the relatively` heavy lead 22 by straps or wires 18 and19, so that the whole structure is rigidified.

The upper section 52 of the lead 23 is desirably angular and connectedto the angular lead extension 14 by wires 29 and 30, the outer ends ofwhich are spot-welded thereto and the inner ends embedded in the glassinsulator 11. Said insulator carries supporting hooks 8|, 82, 83, 84,and 85, over which a filament 32 is draped, the end sections 20 of saidvfilament being fitted over rigidifying wires 40, and filament and wiresconnected, as by welding, to the ends of the lead extension 14 and theupper lead section 52, as indicated at 86 and 81. As in the precedingembodiments, an angular or V-shaped screen 42, for collecting vaporizediilamentary material, may be carried by the insulator 11 throughsupporting spuds 43 and 44.

In view of the foregoing disclosure, it will be seen that I have deviseda novel fuse lead construction, especially adapted for high-wattagelamps of the bipost type, and avoiding weakening the mounts of suchlamps by the inclusion of a fuse in a supporting lead thereof, while atthe same time making it possible to manufacture such lamps economicallyand without serious manufacturing diiiiculties.

Although preferred embodiments of my .invenrtion have been disclosed, itwill be understood' that other modifications may be made within thespirit and scope of the appended claims.

I claim:

l. An electric lamp comprising an envelope, a basefor said envelope, apair of support leads extending from said base, a filament enclosed insaid envelope and supported by said leads, insulating bracing meanstightly fitting a portion of one of said leads, and a fuse associatedwith said bracing means.

2. An electric lamp comprising an envelope, a base for said envelope, apair of support leads extending from said base, a filament enclosed insaid envelope and supported by said leads, one of said leads beingformed in twoparts, insulating bracing means connecting said parts', anda fuse blpassing said bracing means.

3. An electric lamp comprising an envelope, a base for said envelope, apair of support leads extending from said base, a filament enclosed insaid envelope and supportedvby said leads, one of said leads having anintermediate portion enclosed in aninsulating tube and separated by aninsulating member therein, and a fuse exterior of said tube, the ends ofsaid fuse being connected to said lead adjacent opposite ends of saidtube..

4. An electric lamp comprising an envelope, a

base, a pair of support leads extending from said base, a filamentsupported by said leads, one of said leads `being in two segments, andthe adja- 73 cent end portions of said segments tted in an insulatingtube while separated by an insulating member, and an insulated fusedevice parallel- .section to provide a fuse, land an insulating bracingtube tightly tting said lead and enclosing said fuse.

6. An electric lamp comprising an envelope, a base, a pairl of supportleads extending from said base, a lament supported by said leads, one ofsaid leads being formed in two sections connected by va fuse,v aninsulating tube enclosing said fuse and receiving the adjacent ends ofsaid sections, and a wire wound around each end portion of said tube andwith its outer end secured to the lead section adjacent said tube.

7. An electric lamp comprising an envelope, a base, a pair of supportleads extending from said base, a nlament supported by said leads, oneof said leads being formed in two sections, the adjacent portions ofsaid sections being secured to plates, separated by insulating means andconnected together, so as to provide a rigid construction between saidsections, while they are insulated from one another, and a fuseconnecting said insulated lead portions.

8. An electric lamp comprising an envelope, a base, a pair of supportleads extending from said base, a lament supported by said leads, one ofsaid leads being relatively heavy and the other formed in two sections,the adjacent ends of which fit in an insulating tube and are connectedby a fuse enclosed b y'said tube, and means binding said tube to therelatively heavy lead.

9. In a lamp, a fuse lead comprising a pair of conductors, the adjacentends of which tightly nt an insulating bracingtube, and a fuseassociated withsaid conductors to disrupt the passage` of an abnormalnow of electric current therethrough.

`10. In a lamp, a fuse lead comprising a pair of conductors, theadjacent ends o1' which are tightly connected by an insulating bracingtube, and a fuse associated with said conductors to disrupt the passageof an abnormal ow of electric Acurrent therethrough.

11. In a lamp, a fuse lead comprising a-paixof conductors, the adjacentends oi' which tightly t an insulating tube,l and are electricallyinsulated by a plug disposed therebetween, and a fuse associated withsaid conductors to disruptA the passageof an abnormal now ci electriccurrent therethrough 12. In a lamp, a fuse lead for incandescentelectric lamps comprising a pair of conductors, the adjacent ends ofwhich are insulated from each other and enclosed in an insulating tube,and a fuse exterior of said tube, the ends of said fuse being connectedto said conductors adjacent opposite ends of said tube to disrupt thepassage of an abnormal ow of electric current therethrough.

13. In a lamp, a fuse lead for an incandescent electric lamp comprisinga pair oi' conductor sections, adjacent portions of which are fitted inan insulating tube, while separated by an insulating member, a fuse wireparalleling said tube with its ends secured to said lead segments beyondsaid tube, and means enclosing said fuse.

14. In a lamp, `a fuse lead comprising supporting segments joined byafuse, said fuse being enclosed in an insulating tube, the end portionsof which closely receive said segments for rigidifying the connection.

' 15. In a lamp, a fuse lead comprising an insulating tube, a fuseenclosed therein, supporting conductor sections, the adjacent ends ofwhich Vit said tube and are connected by said fuse, and

wires closely wound around opposite ends of said `tube and with theirouter ends secured to said sections.

16. In a lamp, a fuse lead comprising supporting conductor sections, theadjacent portions of said sections being secured to plates, insulatingmeans separating 'said plates, means connecting said plates together soas to providea rigid union between said sections, while maintaining theminsulated from one another, and a fuse connecting portions of saidsections and by-passing said plates.

17. In a lamp, a fuse lead comprising a relatively `heavy supportingconductor, an insulating tube bound thereto and enclosing a fuse,l and

